The SOCAL River Marathon has four distances: Full Marathon, Half Marathon, 10K and 5K. This is a fun course in Southern California. This course runs on the Santa Ana River Trail from Yorba Linda to Huntington Beach State Park. This route truly spans Southern California from the dryer desert land to areas near Disneyland to the Beach. The course is primarily flat and straight but has a gradual downhill slant following the river to the ocean. This route is two years ago was cleaned up from homeless tents and is not fenced in nightly.